1. Field of the Invention
The invention relates to a lens device, more particularly to a lens device that has an alignment correction unit for adjusting an axis of a lens module.
2. Description of the Related Art
A lens device generally has a lens adjustable for correcting the position thereof so as to achieve optimum optical characteristics for the lens device. U.S. Pat. No. 7,139,138 discloses a conventional lens device including a lens barrel and a lens mounted in the lens barrel. The lens is movable with respect to an optical axis via a guiding unit disposed between the lens barrel and the lens, or a positioning unit sleeved on the lens so as to adjust a lens axis of the lens relative to the optical axis. However, the lens is only movable in transverse directions with respect to the optical axis, so that the adjustment between the lens axis and the optical axis may not be easily conducted.
U.S. Pat. No. 7,187,508 discloses another conventional lens device that includes an alignment correction unit for adjusting a lens axis of a lens module. The alignment correction unit includes a mounting ring, a module barrel mounted with the lens module, an elastically deformable component clamped between the mounting ring and the module barrel, and four screw fasteners extending through the module barrel into the mounting ring for locking the module barrel to the mounting ring. During the adjustment process, the depths of the threaded engagement of the screw fasteners with the mounting ring can be independently adjusted such that the module barrel can be tilted relative to the mounting ring, and that the lens axis of the lens module can be precisely adjusted. However, the structure of this conventional lens device is relatively complicated, and the operation of the alignment correction unit is relatively inconvenient.